Lightning arresters

85.35 Electrical apparatus for switching or protecting electrical circuits, or for making connections to or in electrical circuits (for example, switches, fuses, lightning arresters, voltage limiters, surge suppressors, plugs and other connectors, junction boxes), for a voltage exceeding 1,000 volts. 8535.10 8535.21 8535.29 853 5.30 8535.40 8535.90 - Fuses - Automatic circuit breakers : - - For a voltage of less than 72.5 kV - - Other - Isolating switches and make-and-break switches - Lightning arresters, voltage limiters and surge suppressors - Other This heading covers electrical apparatus generally used in power distribution systems. The provisions of Explanatory Note to heading 85.36 apply, mutatis mutandis, as regards the technical characteristics and the functioning of apparatus for switching or protecting electrical circuits, or for making connections to or in elecmcal circuits. The heading covers apparatus of the kinds described in Explanatory Note to heading 85.36, when for a voltage exceeding 1,000 volts. These include : (A) Fuses and automatic circuit breakers which automatically interrupt the current when its intensity or voltage exceeds a certain limit. (€3) Make-and-break switches specialised for high tension circuits. They are usually of a complex and robust construchon having special devices to prevent arcing, and the may have multiple contacts or be remote controlled by d~fferent means (e.g., cvers, servomotors). These switches are often mounted in containers of metal or insulating material, which have been filled with a fluid (e.g., oil) or a gas, or in which a vacuum has been created. (C) Lightning arresters. These are rotective devices designed to protect high tension cables or electrical installations from tl! e effects of lightnin ; they consist of a device normall insulating to the high tension line but which breaks own and becomes a conducting pati! to earth in the event of exceptionally high voltages which otherwise would damage the line or electrical installation. Among the many types are metal oxide arresters, carbon granule arresters, arresters consisting of a horned spark gap or guard shield mounted on an insulator or an insulator chain, electrolytic arresters, etc. However, lightning arresters based on the principle of radioactivity are classified in heading 90.22. 'f (D) Voltage limiters. These are devices intended to ensure that the potential difference between two conductors or between the conductors and the earth does not exceed a predetermined value. These devices are sometimes constructed in the same manner as discharge lamps, but not being usable for lighting purposes, they cannot be considered as lamps. However, the heading does not cover automatic voltage regulators (heading 90.32). (E) Isolatin switches are used for isolating sections of a line; they are of the slow break type, but unl' e make-and-break switches they are not generally intended to be used when the d circuit is loaded. (F) Surge or spike su pressors. These are assemblies of coils, ca acitors, etc., inserted in series or in paralle with a line or electrical ap aratus to absor hi@ frequenc sur es. Simple coils or capacitors used on their own or this purpose rernaln classifiedl in geir respective headings. P P f PARTS Sub'ect to the general provisions regarding the classification of parts (see the General Exp anatory Note to Section XVI), parts of the apparatus of this heading are classified in heading 85.38. The heading excludes assemblies (other than simple switch assemblies) of the apparatus mentioned above (heading 85.37).